Saw-sharpening machine.



J. P. HEDSTROM. SAW SHARPENING MACHINE.

APPLIUATION FILED JAN. 9, 1905.

Patented Aug. 3, 1909.

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J. P. HEDSTROM. SAW SHARPENING MACHINE.

APPLICATION FILED JAN. 9, 1905.

930,178. Patented Aug. 3,1909.

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J. P. HEDSTROM. SAW SHARPENING MACHINE. APPLICATION FILED JAN. 9, 1905.

Patented Aug. 3, 1909.

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n x 1 7 5 n WQ\ m J Qb wh Q W E a 5 1% %U K WW mac J. P. HEDSTROM. SAWSHARPENIN G MAGHINE. APPLICATION FILED JAN. 9, 1905.

UNITED STATES PATENT OFFICE.

JOHN PATRICK HEDSTROM, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNEASSIGNMENTS, TO HANCHETT SWAGE WORKS, OF BIG RAPIDS,- MICHIGAN, ACORPORATION OF MICHIGAN.

SAW-SHARPENING MACHINE.

To all whom it may concern:

Be it known that I, J OHN PATRICK HED- s'rnoar, a citizen of the UnitedStates, residing at Chicago, in the county of Cook and State ofIllinois, have invented a new and useful Saw-Sharpening Machine, ofwhich the following is a specification.

My invention relates to saw sharpening machines operated by power andwhich automatically feed the saw tooth by tooth under a reciprocatinggrinding wheel, especially adapted for band saws and the objects of myimprovements are first to provide a novel and adjustable automaticshifting means for the grinding wheel; second, provide a new simple andefficient driving means for the grinding wheel; third, to so arrange thefeed finger driving mechanism that no perceptible lost motion will becaused by the springing of the parts; fourth, to arrange a connectionbetween the two feed fingers whereby the adjustment of one finger willadjust both; fifth, to facilitate the accurate stoppingof the feed armwithout bringing a strain on the feed finger; sixth, to provide a takeup for the lateral wear on the feed finger; seventh, to make a novel andsimple constructionwhereby the machine can be adjusted to sharpen adouble edged saw, and still other objects to become apparent from thedescription to follow.

I am aware that automatic saw sharpening machines have been made beforemy invention, and these have always had some more or less seriousobjectionable features which I aim to overcome by my invention which isillustrated on the accompanying five sheets of drawings forming apart ofthis specification in which Figure 1, is a front elevation of thecomplete machine; Fig. 2, is a plan of the same; Fig. 3, is a section online 33 of Fig. 1; partly in elevation and with parts omitted; Fig. l,is a detail of the feed finger and its connections; Fig. 5, is a plan ofa connecting rod shown in Fig. i; Fig. 6 is a front view in detail ofthe mechanism for shifting the grinding wheel; Fig. 7, is a section on77 of Fig. 6; Fig. 8, is a longitudinal section through the double edgesaw support forming a part of my invention; Fig. 9, is a section on 99of Fig. 8; Fig. 10 is a detailed plan view of the feed finger partly insection and its associated parts; Fig. 11, is a front elevation of thesame; Fig. 12, is a Specification of Letters Patent.

Application filed January 9, 1905.

Patented Aug. 3, 1909.

Serial No. 240,326.

bottom plan of the feed finger broken away; Fig. 13, is a plan of thefeed finger back stop block and Fig. 14:, is a plan of the feed arm stopblock.

Similar reference characters refer to similar parts throughout theseveral views.

The frame of the machine consists of the two side members 1 and 2, therear member 3, the front member 4., the front plate and the top 6, towhich different brackets and blocks are secured. The main driving shaft7 is at the rear of the machine journaled in the bearing brackets 8 and9 secured to the frames 1 and 2 respectively.

Secured to the shaft 7 adjacent to the bracket 8 are the belt wheels 10and 11 and mounted loosely on said shaft between the wheels 10 and 11 isthe belt wheel 12. Two belts a straight one and a crossed one which passaround the same wide pulley on a counter shaft not shown, pass aroundthe pulleys 10 and 12 as shown in Fig. 2, and are arranged to be shiftedto occupy a position on the pulleys 12 and 11.

Band saws are made right and left hand, and the machines for sharpeningthem must be made right and left hand; the machine which I haveillustrated is a left hand machine. in the grinding machine it encirclesthe machine. It is possible to sharpen a right hand saw on a left handmachine, by placing the saw into the machine so that it does notencircle the machine and reversing the di rection of rotation of thegrinding wheel. The direction of rotation of the grinding wheel is thesame as that of the driving shaft 7, hence if the direction of rotationof the driving shaft 7 is reversed the direction of rotation of thegrinding wheel is reversed. The direction of rotation of the drivingshaft 7 is reversed by shifting the belts on to the wheels 12 and 11.

The grinding wheel 13 is secured to the end of the spindle 14 which isjournaled in the bearings 15 on the gate 16, which is arranged to slidein the frame 17. The frame 17 is adjustably secured to the top frame 6in such manner that it can be swung in an are about an axis which is atright angles to the saw blade. I have shown one means of securing theframe 17 to the top 6 but any desired means may be adopted, in place ofthat shown, which consists of an arm 18 integral with the frame 17provided with When the saw is in proper position an arcuate slot 19 andclamping bolts 20 to secure said arm 18 to a bracket 21 provided with anarcuate slot concentric with the slot 19.

Different saws are provided with. teeth in,- clined at different anglesand to grind these properly the grinding wheels 13 must be ad justed tothe proper angle; this is accomplished by adjusting the frame 17 to anydesired angle by the construction described.

To drive the grinding wheel 13 a pulley 22 is secured on the spindle orshaft 14 and a belt drive 23 connects this pulley to a large pulley 24secured on the drive shaft 7. At some point intermediate the pulley 22and pulley 24 preferably secured to the rear part of the top 6 are twoidlers 25 over which is passed the belt 23 which is preferably a roundbelt. The idlers 25 are-conveniently mounted to serve as belt tightenerson a bracket 26 arranged to be adjusted by means ofthe slot and bolt 27.When the frame 17 is adjusted to difierent angles obviously the pulley22 is also moved to a clifferent position, and to be able to shift theidlers 25 to be in alinement with pulleys 24 and 22, the bracket 26 isarranged to have lateral adjustment; by being secured to a plate 28provided with the slots 29 through which pass the bolts 30 to secure theplate 28 to the top 6. To adjust the plate 28 laterally the bolts 30 areturned loose and the attendant moves the plate, bracket 26 and idlers 25to the desired posltion by hand after which the bolts 30 are againturned to clamp the plate 28 in position. The bracket 26 is similarlyadjusted on the plate 28, but instead of the attendant moving the sameby hand it may be accomplished by providing a screw 31 threaded into alug or bracket on the plate 28 and resting against the bracket 26.

The grinding wheel 13 must be revolved swiftly to accomplish the workdesired of it, and when it becomes reduced in diameter from constantwear, the speed of the spindle 14 must be increased to retain the sameperipheral speed of the grinding wheel. This is attained by providing aplurality of different sized pulleys 24 on the shaft 7 and a pluralityof different sized pulleys 22 on the spindle 14. To increase the speedof the spindle 14 a larger pulley 24 and a smaller pulley 22 isconnected by the belt 23. Besides rotating the grinding wheel 13 thedrive shaft 7 communicates power to a cam shaft 32 to which are secureda cam 33 for raising and loweringthe-grinding wheel 13 and a cam 34 forfeeding the saw along. The shaft 32 is j ournaled in thefront frame 4and the rear frame 3. An intermediate counter shaft is also journaled inthe front frame 4 and the rear frame 3 parallel to the shaft 32, and isoperatively connected to. the shaft '32 by means of the large belt wheel36 secured to shaft 32, the small belt wheel 37 secured to shaft 35 andthe belt 38. The shaft 35 is driven by the shaft 7 through the medium ofa large friction disk 39 secured to the end of shaft 35 and a smallfriction wheel 40 secured on shaft 7. The disk 39 is secured on theshaft 35 to have longitudinal movement thereon but prevented fromrotating on said shaft as by a feather; and a coiled expanding spring 41is interposed between the disk 39 and the rear frame 3 to constantlypress the disk 39 which is preferably metal against the wheel 40 whichis preferably paper. From the description thus far given it will be seenthat the speed of the cam shaft 32 is Very much less than the speed ofthe spindle 14, which is an absolute necessity in machines of thisclass. It is sometimes very desirable to change the comparative speed oftheshaft 32 and shaft 7; as for instance when a very small cut is beingtaken off of the saw'teeth. It will be understood that the greater thespeed of the cam shaft 32' is, the faster the saw will be fed alongthrough the machine, because as will be described every revolution ofthecam shaft 32 moves the saw along one tooth. l/Vhen it is desired to feedthe saw along slowly the friction wheel 40 is moved alongon shaft 7until it contacts the disk 39 near its peripheral edge and is thensecured to shaft 7 as by a set screw; and when it is desired to feed thesaw along fast the friction wheel 40 is secured to shaft 7 so that itwill contact the disk 39 near its center: Shafts 7 and 35 should lie inthe same horizontal plane to derive the best possible results from thefrictional driving means between them, just described. In operation thecam shaft 32 must always rotate in the direction indicated by the arrowsin Figs. 2, 4 and 6; so that when the direction of rotation of the shaft7 is reversed to grind a right handsaw, as above referred to, thefriction wheel 40 is shifted on the shaft 7 to a position beyond thecenter of the disk 39.

To the rear of the sliding frame 16 which carries the grinding wheel issecured a swiveled post 42, provided with a screw-threaded hole 43,through which is fitted the long screw threaded rod or shaft 44. Theupper end of the rod 44 is provided with a hand wheel by means of' whichit can be turned, and the lower end ofthe rod 44 is smooth and rests ina socket provided in the end connection 45, which is pivotally connectedto an adjustable pin or bolt 46, secured in the arcuate slot 47,provided in the plate 48. The plate 48 is adjustably secured to the freeend of a long arm- 49 pivoted atone end 50 to the front frame 4. The arm49 is provided preferably directly below the plate 48 with an elongatedopening through which theshaft 32 passes. The cam 33 is secured tothe'shaft 32 adjacent to the arm 49, and

an antifriction roller 51 which is secured to the arm t9 below the shaft32 is held in constant contact with the cam 33 by a strong contractingcoiled spring interposed between the arm L9 and the top frame 6. The

spring 52 has a strong enough tension to overcome the combined weight ofthe arm 49, plate lS-rod stat, sliding frame 16, grinding wheel 13 andthe bearings, spindle, etc. which are carried by the frame 16. By thisconstruction the enormous weight of these parts is removed from the camand cam shaft used to operate these parts, thus prolonging the life ofthese working parts. Furthermore it will be seen that the gate 13 withthe grinding wheel 13 will only lower and feed against the saw by forceof gravity because the lower end of rod e4. fits loosely in the socket45. This guards against any serious accident taking place from toorapidly feeding the grinding wheel against the saw. In case the spring52 should at any time give outor become broken an antifriction roller 53is secured to the arm 49 above the cam 33 w iich can be used temporarilyuntil the proper repairs can be made.

The slot 47 is provided in the plate 48 to enable the adjustment of themovement of the gate 16 to longer or shorter teeth in the differentsaws, and to increase the distance of this adjustment the plate 48 ispivoted to the arm 49 at 54- and is provided with the arcuate slot 55through which bolt is passed to secure it to the arm 49. The operationis that as the shaft 32 rotates the cam 33 will 0 aerate the arm 49against the tension of the spring 52 and cause the gate 16 and thereforethe grinding wheel 13 to move up and down. To finally adjust thegrinding wheel 13 to the saw, the screw threaded rod 4ais turned in theswiveled pos a2, and

fter it is properly adjusted the rod as may be locked by a set screw orotherwise.

The saw 56 in the drawings is shown to be a double edged left hand sawand in Fig. 1 is broken away to illustrate the machine to betteradvantage. To retain the upper edge of the saw i. 6., the edge beingsharpened, in proper alinenient under the grinding wheel the lower edgeof the saw is supported in a guide to be described and the upper edge isclamped against a shoe 57 secured to the front plate 5, by a springpressed pivoted clamp 58. The clamp 58 is preferably pivoted at 59 ontwo set screws secured in lugs extending forward from the front plateThe spring 60 for said clamp is preferably adjustably and pivotallysecured to the front plate 5 at 61, and is provided with a handle 62 topull it away from the clamp and turn it on its pivot.

The mechanism constructed for feeding or moving the saw along tooth bytooth em bodies several novel features and advantages which have neverheretofore been used, and consists of the feed finger 63 provided with apush pin 64, pivoted to the upper free end of the feed arm 65, which ispivoted at 66 to the front frame a, and is connected nearest its upperend by the connecting rod 67 to the free end of the lever 68 which ispivoted at 69 to the front frame 4: and is provided with theantifriction roller 70 which is held in constant contact with the cam 34by a coiled contracting spring 71 connected between the top end of thelever 68 and the top 6. The finger 63 is moved back and forward closealongside the saw 56 by the rotation of the cam 34 by means of theconnections just described. The pin 64L extends out from one side of thefinger 63 into the path of the saw 56 and catches into the front side ofthe teeth of the saw when moving in one direction and slides over theback of the teeth when moving in the other direction. When the pin 64;catches against the front side of a tooth it moves the saw along thedistance of one tooth. To prevent any downward thrust on the saw by thepin 64 when it is moving the saw the bottom side of the finger 63 ridesalong on top of the shoe 57 From constant use the contacting surfaces ofthe finger G3 and shoe 57 become worn and require to be replaced. Tofacilitate the cheap and easy replacing of these parts, I secure to thebottom of finger 63 the wearing plate 72 by screws 73 see Figs. 11 and12 and to the top of the shoe 57 the wearing plate 74. The plate 7 1 issecured to the shoe 57 by inserting the acutely bent end of the plate 74into an inclined slot 75 in the shoe 57 and securing the remaining endof said plate to said shoe by a set-screw. The finger 63 in operationmoves a greater distance than the distance from one tooth of the saw toanother so that when moving back the pin 64: drags up over the back ofthe next succeeding tooth thereby lifting the finger 63 from the shoe57. Heretofore when the pin 64 is passed beyond the point of the toothin its backward movement the finger 63 was allowed to drop by gravity,and the full force of the finger thus falling was exerted against theback of the next succeeding tooth by the pin 64 contacting with saidtooth. This striking force was greater or less according to the weightof the finger 63, and to a degree equal to the striking force tended tomove the saw backward. To prevent this gravitating force of the fingerstriking against the back of the saw teeth I provide on the top edge ofthe front plate 5 underneath and slightly to the rear of the finger 63an inclined lug 76 provided with means for adjusting it toward or awayfrom the finger The lug 7 6 is so adjusted that the bottom of the finger63 will strike upon the same when the pin 64 is moved back beyond thepoint of a tooth of the saw, thus the gravitating force of the &

finger 63 will be exerted against the lug 76 and will not affect theposition of the saw.

To adjustably pivot the finger 63 to the feed arm the upper end of thearm 65 is provided with the rectangular opening 77 in which is fitted toslide the rectangular block 78. An adjustingscrew 79 is threaded throughthe block 78 and passed loosely through perforations provided in twoopposing walls of the opening 77 on the exterior of which it is providedwith a hand wheel on the one end and locking nuts on the remaining end.A cylindrical sleeve 80 extends through an aperture provided therefor inthe block 78, and a bolt 81 extends longitudinally through said sleeve,see Fig. 10. The finger 63 is provided with two side ,members 82 and 83which are tightly clamped against the ends of the sleeve 80 by the bolt81, the sleeve 80 being slightly longer than the block 78. The members82 and 83 are rigidly but adjustably secured together some distance infront of the arm 65 by a screw-threaded rod 8 1 secured rigidly to onemember and passing through a per- '65 is what feeds the saw forward, andit is important that this forward movement be positively limited and thearm be stopped at the same point each time. Of course the forward throwof the feed arm 65 it will be understood is approximately regulated byshifting one end of the connecting bar 67 in the arcuate slot 86provided in the lever 68,

but unless some provision is made to prevent it the momentum of thelever 68, connecting rod 67, arm 65 and its connections would cause thearm 65 to stop at different points at the end of its forward movement-s.To provide an adjustable stop for the arm 65 a plate v87 having anelongated opening 88 is secured to the top 6 in such position that thearm 65 extends through the opening 88. Mounted to slide on the plate 87is the stop block 89 provided with the elongated opening 90 throughwhich the arm 65 projects and one edge of said block extends under aflange91 arranged to be secured to the plate 87.. The end 92 vof theblock 89 is provided with a screw threaded hole into which is fitted ascrew 93 passed through a smooth hole in a lug 9st on plate 87, and isprevented from having longitudinal movement in said lug by a collar onone side thereof and a hand wheel 95 on the other .side thereof whichare fixed to said screw 93. The arm 65 is stopped in its forwardposition by the screw 93 and then clamped in such position by the flange91.

As previously stated the band saw encircles the machine when in positionto be sharpened, and besides being supported by a guide secured to themachine it is supported by a plurality of standards not showndistributed at proper intervals around the entire loop of the saw. Thefeed arm 65 moves one side of the saw loop and to properly move the sawaround the opposite side of the saw loop must be moved by a feed armalso. Heretofore the mechanism employed to operate the feed arm remotefrom the machine required a separate adjustment each time that the feedarm on the machine was adjusted to feed differently. The mechanism whichI employ is automatic inrits adjustment, 2'. 6. when the feed arm on themachine is adjusted the other feed arm is also adjusted; which consistsof extending the pivot 66 of the feed arm 65 in the shape of a shaft andsecuring thereto a segmental gear 97 which meshes with a segmental gear98 secured to a shaft 99 to which is secured the feed arm 100 which isprovided adjustable guide and support 103 which is provided with arearwardly extending rectangular block arranged to slide in the vertical way 104: provided in the front plate 5. A rear plate 105 issecured to the mo tangular block to prevent it from leaving the way 104and has a rearwardly extending lug or boss 106 provided with a verticalscrewthreaded hole, into which is fitted the vertical screw 107. Thelower end of the screw 107 below the boss 106 passes freely through aperforation in a lug 108 on the rear side of the plate 5. A collar 109is fixed on the screw 107 to rest on the upper side of the lug 108 andprevent any downward movement of the screw 107 through the lug 108. Thelower end of the screw 107 is provided with a hand wheel 110 to turn thescrew to adjust the guide 103. A thumbscrew 111 maybe provided in theplate 5 for clamping the screw 107 in place after it has been adjusted.

To make an absolutely level seat in the guide 103 for the saw to rest onand to prevent the sharpened teeth being made dull, the bottom of thesaw groove in the guide 103 is provided with a plurality of hardenedsteel bars 112 having their upper surface made in the form of alongitudinal ridge, and upon these blocks 112 is laid an endlessmovement by striking against the end 296 band of spring steel 113. Thesaw teeth rest on the top of this steel band 113, and the frictionalcontact between the saw-teeth and band 113 being greater than thefrictional contact between the band 113 and the blocks 112, the band 113will travel along with the saw and relieve the teeth of all friction.

It will be understood that numerous changes can be made in parts of thismachine in construction and arrangement without in the least departingfrom the spirit of the invention.

Having thus fully described my invention what I claim as new and desireto secure by Letters Patent of the United States is 1. In asaw-sharpening machine, a suitable frame, a gate carrying a grindingwheel guided to slide in a vertical plane, a driving shaft mounted insaid frame, an endless belt for communicating power from said drivingshaft to said grinding wheel, a pivoted arm arranged to have its freeend depressed by acam, a compound push rod free to extend in lengthhaving its upper end pivotally connected to said gate and its lower endpivotally connected to the free end of said arm, means operativelyconnected to said driving shaft for rotating said cam, and a springconnected to the free end of said arm to normally hold it in a raisedposition against said cam, the parts being so arranged and connectedthat the grinding wheel will normally be held in a raised position bysaid spring and will lower by gravity when the free end of said arm isde pressed.

2. In a saw sharpening machine, a gate carrying a grinding wheel guidedto slide in a vertical plane, means for driving said grinding wheel, apivoted arm arranged to have its free end depressed by a cam, a compoundpush rod free to extend in length having its upper end pivotallyconnected to said gate and its lower end pivotally connected to saidarm, means for rotating said cam, and a spring connected to said arm tonormally hold its free end raised and against said cam, the parts beingso arranged and connected that the grinding wheel will normally be heldin a raised position by said spring and will lower by gravity when thefree end of said arm is depressed by said cam.

3. In a saw sharpening machine, a gate carrying a grinding wheel guidedto slide in a vertical plane, a pivoted arm, means for raising andlowering the free end of said arm, a plate provided with two slotsadjustably secured to the free end of said arm, set screws securing saidplate and said arm together and a rod having its upper end pivotallyconnected to said gate and its lower end pivotally connected to a blockadjustably secured in said slotted plate whereby the range of adjustmentbetween said gate and said arm is materially changed.

a. A guide and support for a saw provided with a slot in its upper sideto receive the saw and an endless band in the bottom of said slot onwhich the saw rests.

5. In a band-saw sharpening machine, a feed arm provided with a feedfinger for moving one side of the saw loop, a second feed arm providedwith a feed finger for moving the other side of the loop, and mechanismconnecting said two feed arms whereby the adjusting of the first namedfeed arm will adjust the second named feed arm.

6. In a band-saw-sharpening machine, a feed arm provided with a feedfinger for moving one side of the saw loop secured to a rockshaft, asecond feed arm provided with a feed finger for moving the other side ofthe saw loop secured to a second rockshaft, and a segmental gear securedto the first named rock shaft meshing with a segmental gear secured tothe second named rock shaft whereby motion and adjustment applied to thefirst named feed arm is transmitted to the second named feed arm.

7. In a saw sharpening machine, a frame, a grinding wheel, means formoving the grinding wheel, a saw guide adjustably secured to said frame,a feed arm and means for actuating said feed arm, and a stop blockadjustably secured to said frame provided with a slot in which the upperend of said feed arm is fitted to move and engage one end of said slot.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses this Qtth day of December 1904: atChicago Illinois.

JOHN PATRICK HEDSTROM.

Witnesses FRANK G. WVESTLUND, NnLs. J OHNSON.

